i am interested in learning about computer security and i have setup a couple of computers running linux.

On the 2 systems i want to install some servers like apache, telnet, ssh, ftp etc so i can learn about penetration testing, is there any particulary servers and version of the servers you would recomend for my project ?

Just wanted to revisit this topic to see if anything has changed in the recent years.

It appears the Damn Vulnerable Linux is currently in dev waiting for Summer 2011.

Are there any other similar distros out there?

Install Windows XP (no service packs) and do not update it. Then install older versions of whatever software you like, also without patching anything. You should then be able to find plenty of exploits to play with.

I would like to do that to gain pen testing experience, but I have no idea where to get XP SP0 installation media and key. I have an XP Pro SP3 CD and, as far as I know, it's not possible to strip back all three Service Packs.